1. Field of the Invention
The present invention relates generally to the control of a defrost heater for a refrigerator and specifically to an adaptive control method and apparatus therefor.
2. Related Art
It is known to provide a defrost heater to a refrigeration unit such as in a domestic refrigerator or freezer appliance. In conventional arrangements, the heater is cycled on the basis of electromechanical timers which accumulate time on the basis of compressor operating time, xe2x80x9crun time,xe2x80x9d or xe2x80x9con time.xe2x80x9d When the timer accumulates a predetermined amount of compressor operating time, the defrost heater initiates a defrost cycle, regardless of the current state of various refrigeration components and environment. This can lead to an inefficient use of energy.
According to one aspect of the present invention, a method for controlling a defrosting apparatus in a refrigerator having a compressor is provided. The method comprises the steps of receiving a demand for defrosting, detecting that the compressor is presently operating, and initiating a defrost cycle after the steps of receiving and detecting.
According to another aspect of the present invention, a method of defrosting a refrigerator or freezer having a compressor and a defrost heater is provided. The method comprises the steps of operating the compressor for a duration and energizing the defrost heater based upon completion of the step of operating the compressor.
According to a further aspect of the present invention, a controller for controlling a defrosting apparatus in a refrigerator having a compressor is provided. The controller comprises a defrost determination means for determining when a defrost cycle is needed, a compressor operation detection means for determining whether the compressor is presently operating, a compressor cycle duration determining means for determining the duration of a prior and a present continuous operation cycle, and a defrost initiation means for initiating a defrost cycle based upon the defrost determination means, the compressor operation detection means and the compressor cycle duration determining means.